nanog mailing list archives

Re: Verizon Fios, WashDC gateway problem


From: Paul Paukstelis <shocksofmighty () gmail com>
Date: Wed, 17 Feb 2016 14:35:07 -0500

I avoided posting traceroute initially after reading the FAQ, but this seems like a case where it can help in diagnostics. Loss starts at the affected device (hop 3) and persists. See mtr report for affected and unaffected gateways:

Host Loss% Snt Last Avg Best Wrst StDev 1. Wireless_Broadband_Router.home 0.0% 673 0.5 0.5 0.4 0.6 0.0 2. L100.WASHDC-VFTTP-123.verizon-gni.net 0.0% 673 6.5 8.1 3.7 90.1 9.6 3. G1-7-3-5.WASHDC-LCR-22.verizon-gni.net 11.2% 673 8.2 8.7 5.1 15.8 1.6
 4. ???
5. 0.ae4.BR2.IAD8.ALTER.NET 10.4% 673 9.0 8.0 5.4 22.1 1.4 6. be3018.ccr41.iad02.atlas.cogentco.com 10.3% 673 7.1 8.2 5.9 15.3 1.2 7. 38.122.63.54 12.3% 673 7.0 8.4 6.2 29.3 2.8 8. ae3-asbnvacyj41.lightower.net 9.4% 672 7.1 8.3 5.8 32.0 2.2 9. 172.85.52.94.lightower.net 10.7% 672 10.0 9.6 7.5 14.3 1.0 10. te1-4.css-fw-r1.net.umd.edu 11.0% 672 12.2 14.8 7.6 287.2 27.2 11. gi6-6.ptx-core-r1.net.umd.edu 7.9% 672 10.5 11.0 7.8 340.5 15.2 12. gi3-2.ptx-dual-r1.net.umd.edu 9.7% 672 11.9 13.1 8.3 265.6 14.3 13. 129.2.168.3 12.6% 672 11.2 10.9 8.5 188.4 7.7

Host Loss% Snt Last Avg Best Wrst StDev 1. Wireless_Broadband_Router.home 0.0% 287 0.5 0.5 0.5 1.2 0.1 2. L100.WASHDC-VFTTP-123.verizon-gni.net 0.0% 287 6.6 14.9 3.7 148.3 22.8 3. G0-10-3-4.WASHDC-LCR-21.verizon-gni.ne 0.0% 287 9.4 14.9 5.3 97.2 19.1
 4. ???
5. 0.ae3.BR2.IAD8.ALTER.NET 0.0% 287 7.8 13.6 5.7 93.6 17.7 6. be3018.ccr41.iad02.atlas.cogentco.com 0.0% 287 8.1 14.0 6.0 94.1 18.5 7. 38.122.63.54 0.0% 287 9.7 15.5 6.0 97.1 19.1 8. ae3-asbnvacyj41.lightower.net 0.0% 287 9.4 16.4 5.9 95.7 19.6 9. 172.85.52.94.lightower.net 0.0% 287 9.1 19.0 7.7 99.7 22.6 10. te1-4.css-fw-r1.net.umd.edu 0.0% 287 9.4 23.9 7.7 269.8 35.7 11. gi6-6.ptx-core-r1.net.umd.edu 0.0% 287 10.7 18.2 8.2 100.4 20.6 12. gi3-2.ptx-dual-r1.net.umd.edu 0.0% 287 12.2 20.5 8.5 172.2 23.7 13. 129.2.168.2 0.0% 287 11.1 16.4 7.7 95.8 19.3


On 02/17/2016 02:14 PM, chris wrote:
packet loss in the middle of the path means nothing if you have no loss at the destination. do you see packet loss on the last mtr hop which is your destination machine?

On Tue, Feb 16, 2016 at 8:54 PM, Paul Paukstelis <shocksofmighty () gmail com <mailto:shocksofmighty () gmail com>> wrote:

    Apologies for a post as a non-expert, but it was suggested that I
    see if any Verizon techs are reading here and to solicit opinions
    on fixing a peculiar problem.

    I noticed about a month ago that all upload traffic from my home
    router (Fios) to a specific work machine was extremely slow. I
    first thought it was an issue with the destination NIC, or
    something with the university gateway. I had normal upload speeds
    to other destination machines in the same building on the same
    subnet, etc. Eventually, I swapped IPs on the two machines, and
    found that the problem had to do with routing to a specific IP,
    not the destination machine itself. I confirmed first with
    wireshark that there was packet loss resulting in constant TCP
    Fast Retransmits when uploading to the affected host IP.
    traceroute showed that the affected and unaffected traffic went
    through different Verizon gateways
    (G1-7-3-5.WASHDC-LCR-22.verizon-gni.net
    <http://G1-7-3-5.WASHDC-LCR-22.verizon-gni.net> and
    G0-10-3-4.WASHDC-LCR-21.verizon-gni.net
    <http://G0-10-3-4.WASHDC-LCR-21.verizon-gni.net>, respectively;
    I've ultimately found that four different gateways are used
    depending on the destination IP). mtr confirmed consistent 10%
    packet loss at G1-7-3-5.WASHDC-LCR-22.verizon-gni.net
    <http://G1-7-3-5.WASHDC-LCR-22.verizon-gni.net>. This tells me
    that there is clearly a problem with this device, but I have yet
    to be able to convince Verizon there is a problem. I thought I
    might just VPN around it, but as luck would have it the university
    VPN IP gets routed through the bad gateway. This has to be
    impacting a significant number of Fios customers in the DC/MD
    area. 25% of all upload traffic (assuming a normal distribution of
    destination IPs) gets routed through this bad device.

    Any thoughts on how to get in touch with someone from Verizon that
    can help with this or any specific ideas on what this problem
    might be which I can try to pass along?

    Thanks.




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